In recent years, there is an increasing need for consolidation of information platforms so as to improve the investment efficiency for IT systems in a corporation. The consolidation helps to gradually integrate processing units composed of individual frames such as a server, a router, and a storage into a single frame. In terms of the server, there is a widespread use of a blade server that mounts multiple servers in single frame for improved space saving and decreases the complicatedness of cabling for the power supply and networking. The blade server uses a thin case, called a blade, to mount elements such as a CPU, memory, and an HDD. Multiple blades are placed in a frame, called an enclosure, to implement high integration of the server. JP-A No. 32153/2002 describes this type of blade server. The storage or the router modularizes constituent elements of the processing unit for ensuring performance and scalability and connects only elements needed for the performance with the frame. For example, the storage modularizes a RAID controller or an HDD disk unit to duplicate the RAID controller and provide scalability of the storage capacity. The router modularizes an external interface function portion, called a line card, to provide scalability of the switch through capacity. In this manner, the present information platform apparatus modularizes processing unit's constituent elements in the processing unit. JP-A No. 215116/2004 describes that type of storage. JP-A No. 50749/2003 describes that type of router.
A system architecture for unifying these processing units can be represented as a complex information platform apparatus that uses one IO switch to connect multiple processing units. The complex information platform apparatus is composed of multiple general-purpose processing modules, an IO processing module to process a disk or an external network, and a management module to manage the complex information platform apparatus. Each module is connected to an IO switch via an adapter. A customer can flexibly change the configuration of the complex information platform apparatus and the function of the processing unit by changing a combination of modules according to needs.
A network switch is provided with the QoS (Quality of Service) to ensure a communication band and a priority for the network. The QoS function is represented by two models, IntServ and DiffServ. The IntServ model ensures the maximum available band or the minimum available band in a switch for a request concerning a given service. A management server manages a service-providing application or a switch. The management server may notify the switch's QoS function of an available band ensuring request composed of an identifier for service identification such as an ID and a corresponding available band. In such case, the switch's QoS function ensures a band dedicated to the switch for the request having the corresponding identifier. The DiffServ model provides priority control between requests in accordance with priority information in a request. The switch's QoS function provides priority control between requests in accordance with an identifier and a predetermined QoS policy. In this case, the identifier is used to identify a priority such as an ID or an address maintained in a request. Internet (http://www.ietf.org/rfc/rfc2998.txt) Integrated Services Over Diffserv Networks, November, 2000 describes this model in detail.